Biomedical subjects

H Iida

Publications and source records attributed to H Iida.

At least 91 records · Page 5Linked to original sources

PubMed2000

Anterolateral thigh flap donor-site complications and morbidity.

The authors examined donor-site complications and morbidity in 37 patients after reconstruction with free or pedicled anterolateral thigh flaps. Intraoperative assessment included damage to the vastus lateralis muscle and whether the main pedicle of the rectus femoris muscle had been killed. Postoperative assessment of the donor site included wound healing, range of motion, muscle strength, gait, and sensation. Patients were surveyed with a questionnaire about fatigue in their activities of daily life and the appearance of the donor site. All 32 patients who underwent primary skin closure could perform activities of daily life normally, and most (87.5 percent) reported that donor-site appearance was satisfactory. However, the severity of donor-site dysfunction was related to the degree of damage to the vastus lateralis muscle, and most patients (87.5 percent) had some loss of sensation at the anterolateral aspect of the thigh. Because of adhesions between the meshed skin graft and the underlying fascia, range of motion at the hip and knee was limited in significantly more patients who had received split-thickness skin grafts (60 percent) than patients who had undergone primary skin closure (3.1 percent). Therefore, wider flaps or flaps harvested nearer the knee may increase donor-site morbidity. The authors concluded that the incidence of long-term morbidity with the anterolateral thigh flap is low, although it is increased when the flap includes the vastus lateralis muscle or is wider and requires additional skin grafting at the donor site.

Adult↗

PubMed2000

Comparison of cerebrovascular effects of intravenous cocaine injection in fetal, newborn, and adult sheep.

Cocaine may cause stroke, intracranial hemorrhage, seizures, and neurobehavioral abnormalities in fetuses, newborns, and adults, and there could be developmental and/or species differences in mechanisms for these cocaine-induced cerebrovascular effects. To evaluate developmental differences in responses to cocaine, we compared the cerebrovascular and metabolic responses to a 2 mg/kg iv cocaine dose in unanesthetized fetal (n = 8, previously reported, direct fetal injection), newborn (n = 6), and adult (n = 12) sheep. We measured cerebral blood flow, mean arterial blood pressure, and arterial and venous O(2) content, and we calculated cerebral O(2) consumption and cerebral vascular resistance at baseline and at 30 s and at 5, 15, and 60 min after cocaine injection. Cerebral blood flow increased 5 min after injection in the fetus and newborn, but not until 15 min in the adult. In the fetus, cocaine caused a transient cerebral vasoconstriction at 30 s; in all three groups, cocaine caused cerebral vasodilation, which was delayed in the adult. Cerebral metabolic O(2) consumption increased 5 min after injection in the fetus and newborn, but not until 15 min after injection in the adult. Arterial O(2) content decreased 5 min after injection in the fetus and 15 min after injection in the adult. We speculate that clinical differences in response to cocaine injection may be explained, in part, by these developmental differences in the cerebrovascular and metabolic responses to cocaine.

Animals↗

PubMed2000

Ca2+ signal is generated only once in the mating pheromone response pathway in Saccharomyces cerevisiae.

The mating pheromone, alpha-factor, of the yeast Saccharomyces cerevisiae binds to the heterotrimeric G protein-coupled cell surface receptor of MATa cells and induces cellular responses necessary for mating. In higher eukaryotic cells, many hormones and growth factors rapidly mobilize a second messenger, Ca2+, by means of receptor-G protein signaling. Although striking similarities between the mechanisms of the receptor-G protein signaling in yeast and higher eukaryotes have long been known, it is still uncertain whether the pheromone rapidly mobilizes Ca2+ necessary for early events of the pheromone response. Here we reexamine this problem using sensitive methods for detecting Ca2+ fluxes and mobilization, and find no evidence that there is rapid Ca2+ influx leading to a rapid increase in the cytosolic free Ca2+ concentration. In addition, the yeast PLC1 deletion mutant lacking phosphoinositide-specific phospholipase C, a key enzyme for generating Ca2+ signals in higher eukaryotic cells, responds normally to the pheromone. These findings suggest that the receptor-G protein signaling does not utilize Ca2+ as a second messenger in the early stage of the pheromone response pathway. Since the receptor-G protein signaling does stimulate Ca2+ influx after early events have finished and this stimulation is essential for late events in the pheromone response pathway [Iida et al., (1990) J. Biol. Chem., 265: 13391-13399] Ca2+ may be used only once in the signal transduction pathway in unicellular eukaryotes such as yeast.

Calcium↗

PubMed2000

Effects of orchidectomy on bone metabolism in beagle dogs.

The effects of orchidectomy on bone metabolism in male beagle dogs were examined using twelve 2-year-old dogs that were orchidectomized. The dogs' bilateral iliac bones, double-labeled with tetracycline and calcein for the histomorphometry, were obtained from three dogs prior to orchidectomy and at 3, 6, 9, and 12 months afterwards. The serum biochemical constituents related to bone metabolism were examined before and every month after orchidectomy. Between 1 and 6 months after orchidectomy, the value of serum testosterone decreased (1 month), while the levels of parathyroid hormone, calcitonin, total calcium, osteocalcin, and alkaline phosphatase activity increased significantly, indicating a high bone turnover. The mean trabecular thickness and the fraction of labeled osteoid surface decreased significantly 3 months after orchidectomy, but other histomorphometric parameters were unchanged. In the period 7-12 months after orchidectomy, the parathyroid hormone level increased ever and above that of the first 6-month period, while the levels of calcitonin, osteocalcin, alkaline phosphatase activity, and phosphorus decreased. The bone volume, mean trabecular thickness, and the fraction of labeled trabecular surface decreased significantly compared with the pre-orchidectomy values. These findings indicate an imbalance in bone metabolism (i.e. bone resorption > bone formation). These results indicate that a loss of bone volume accompanied the fall in sex hormone levels following orchidectomy and suggest that the orchidectomized dog is available as an animal model for studying osteoporosis caused by hypogonadism and the decline of sex functions in men.

Alkaline Phosphatase↗

PubMed2000

Cemented total hip arthroplasty with acetabular bone graft for developmental dysplasia. Long-term results and survivorship analysis.

Although the technique of autogenous acetabular bone grafting has been widely used to augment containment of the acetabulum in total hip arthroplasty (THA) for developmental dysplasia, the role of this technique in improving long-term results remains controversial. We present the long-term results of cemented THA with acetabular bone grafting in 112 patients (133 hips) in order to clarify the factors which affect the outcome. The mean follow-up was for 12.3 years (8 to 24). Kaplan-Meier survivorship analysis predicted a rate of survival of the acetabular component at 15 years of 96% (95% confidence interval (CI) 92 to 99) with revision for aseptic loosening as the endpoint, and of 75% (95% CI 65 to 85) when radiological loosening was used. Parametric survivorship analysis using the Cox proportional-hazards model indicated that trochanteric nonunion, lateral placement of the socket, and delayed trabecular reorientation of the bone graft were risk factors for loosening of the acetabular component. Our findings have shown that autologous acetabular bone grafting is of value for long-term success provided that the risk factors are reduced.

Acetabulum↗

PubMed2000

Porous apatite-wollastonite glass-ceramic as an intramedullary plug.

We evaluated the efficacy and biocompatibility of porous apatite-wollastonite glass ceramic (AW-GC) as an intramedullary plug in total hip replacement (THR) for up to two years in 22 adult beagle dogs. Cylindrical porous AW-GC rods (70% porosity, mean pore size 200 microm) were prepared. Four dogs were killed at 1, 3, 6 and 12 months each and six at 24 months after implantation. Radiological evaluation confirmed the efficacy of porous AW-CG as an intramedullary plug. Histological evaluation showed osteoconduction at one month and resorption of the porous AW-GC, which was replaced by newly-formed bone, at 24 months. Our findings indicate that porous AW-GC can be used clinically as an intramedullary plug in THR.

Animals↗

PubMed2000

Association of the developing acrosome with multiple small Golgi units, the Golgi satellites, in spermatids of the musk shrew, Suncus murinus.

The spermatozoa of the musk shrew, Suncus murinus, have a fan-like giant acrosome with a diameter of approximately 20 mm. The aim of this study was to investigate how this giant acrosome is constructed in the musk shrew spermatid and, in particular, how the Golgi apparatus involved in acrosome formation behaves. The behaviour of the Golgi apparatus was monitored by confocal laser scanning microscopy with antibody against a Golgi-associated Rab6 small GTPase. In the early Golgi phase, small Golgi units, the Golgi satellites, localized as a large aggregate in the juxtanuclear cytoplasm. As acrosome formation progressed, the Golgi satellites gradually dispersed, associated with proacrosomal vesicles and an acrosomal vesicle, and finally became distributed as multiple small units over the whole surface of an acrosomal cap in the round spermatid. The mode of acrosome formation in musk shrews was distinctly different from that in rats and mice, in which the Golgi apparatus remains as a single unit throughout acrosome formation. In musk shrews, the proacrosomal vesicles formed successively by the Golgi satellites coalesced, one after another, into a potential acrosomal vesicle. This process may result in further enlargement of the acrosome. The results of the present study indicate that Golgi satellites are necessary for the biogenesis and development of the giant acrosome in musk shrew spermatozoa.

Acrosome↗

PubMed2000

A new method for bone marrow cell harvesting.

To minimize contamination of bone marrow cells (BMCs) with T cells from the peripheral blood, a new "perfusion method" for collecting BMCs is proposed using cynomolgus monkeys. Two BM puncture needles are inserted into a long bone such as the humerus, femur, or tibia. One needle is connected to an extension tube and the end of the tube is inserted into a culture flask to collect the BM fluid. The other needle is connected to a syringe containing 30 ml of phosphate-buffered saline. The solution is pushed gently from the syringe into the medullary cavity, and the medium containing the BM fluid is collected into the culture flask. There is significantly less contamination with peripheral blood, determined from the frequencies of CD4(+) and CD8(+) T cells, when using this method (<6%) than when using the conventional method (>20%) consisting of multiple BM aspirations from the iliac crest. Furthermore, the number and progenitor activities of the cells harvested using this "perfusion method" are greater than those harvested using the conventional aspiration method. This perfusion method was carried out 42 times using 15 cynomolgus monkeys, and no complications such as pulmonary infarction or paralysis were observed. These findings suggest that the "perfusion method" is safe and simple and would be of great advantage in obtaining pure BMCs, resulting in a less frequent occurrence of acute graft-versus-host-disease in allogeneic BM transplantation.

Animals↗

PubMed2000

Mixed connective tissue disease with multiple organ damage: successful treatment with plasmapheresis.

A 24-year-old-woman with mixed connective tissue disease (MCTD) developed multiple organ failure, disseminated intravascular coagulation (DIC), metabolic acidosis, and respiratory and renal failure resulting from visceral vasospasm, so-called visceral Raynaud's phenomenon. After plasmapheresis, the condition of multiple organ failure was markedly improved. The successful treatment with plasmapheresis was dependent upon the removal of immune complexes in serum and improvement of visceral circulation. Thus plasma exchange is recommended as a possible a treatment for multiple organ damage in MCTD.

Acidosis↗

PubMed2000

Protein expression and constitutive phosphorylation of hematopoietic transcription factors PU.1 and C/EBP beta in acute myeloid leukemia blasts.

The transcriptional activity of transcription factors is regulated by phosphorylation. The uncontrolled expression and constitutive activation of transcriptional regulators have been reported to cause malignant diseases. However, little is known about the phosphorylation status of tissue-specific transcription factors in human primary malignancies. Here we present the first insights into both protein expression and phosphorylation of transcription factors in a large-scale study of patients with acute myeloid leukemia (AML). We examined the expression and phosphorylation status of hematopoietic transcription factors PU.1 and C/EBP beta detected by the retarded mobility of the phosphorylated forms of the proteins. The rate of protein expression differed among French-American-British (FAB) subclasses. The expression of C/EBP beta and PU.1 were detectable in 77% and 61%, respectively, of 90 AML samples examined. The expressed PU.1 and C/EBP beta was always accompanied with both phosphorylated and unphosphorylated forms of PU.1 and C/EBP beta, respectively. Statistical significance was observed between PU.1 expression (phosphorylation) and FAB classification (M0, M4, or M5 versus M2 or M3, P < .0001). PU.1 and C/EBP beta were simultaneously detected in all M0, M4, M5 and peripheral blood monocytes, whereas in M2 and M3, the expression of the 2 transcription factors varied among samples. Examination of protein expression and phosphorylation of these lineage-specific molecules may help us to understand the functional characteristics of AML.

Acute Disease↗

PubMed2000

[Quantitative evaluation for scatter and attenuation correction in 99mTc SPECT--multicenter cooperation phantom study].

A multicenter cooperation phantom study was conducted to evaluate the accuracy of a triple energy window scatter correction technique in combination with various attenuation correction methods for 99mTc single photon emission computed tomography (SPECT) imaging. Six centers participated in this research and the data obtained with seven SPECT instruments were analyzed. The phantom used in the experiment was a 20 x 10 cm cylinder filled with homogeneous 99mTc solution, containing two kinds of cold spots (cold rod phantoms). One had a water-filled cylinder 5.5 cm in diameter positioned 2.5 cm from the center. The other contained 6 water-filled cylinders of various sizes. Contrasts of cold regions were in the range from 74% to 120% (true 100%). Another phantom had the shape of a pie-chart divided into six chambers symmetrically positioned in a cylinder 20 cm in diameter and 10 cm in height. Each chamber had volume of 480 ml and contained homogeneous 99mTc solution of different concentrations. This phantom was used to test for linearity between the radio activity concentration and reconstructed count density (linearity phantom). The intercept of the regression line obtained from the linearity phantom was 8.4 kBq ml-1 without scatter correction and -6.8 kBq ml-1 with scatter correction. Contrast was in the range from 78% to 132% (true 100%). The mean relative error for the measured activity concentration was 4.9% +/- 3.5% (mean +/- sd).

Phantoms, Imaging↗

PubMed2000

A case of congenital afibrinogenemia: fibrinogen Hakata, a novel nonsense mutation of the fibrinogen gamma-chain gene.

Congenital afibrinogenemia due to a novel homozygous nonsense mutation of the fibrinogen gamma-chain gene, fibrinogen Hakata, was found in an 18-year-old Japanese girl who had received supplemental fibrinogen therapy since she was 4 months old. The plasma fibrinogen concentrations of the proband were measured as less than 10 mg/dl by a functional method and less than 17 mg/dl by an immunological method. Fibrinogen concentrations of her family were in the range of 94-164 mg/dl. The proband and her family had no other clinical symptoms. Genomic DNA of the proband and her family was isolated from leukocytes, and all exons of fibrinogen subunits and their intron/exon boundaries were analyzed. A genetic mutation, a guanine-to-thymine (G-to-T) transversion at the nucleotide position of 5860, was identified on exon 7 of the gamma-chain gene. This mutation changed the codon for the 231st residue of the gamma-chain from GAG (Glu) to TAG (stop). No other mutation was observed. Aalpha, Bbeta and gamma chains were observed in plasma of the heterozygous family members. However, only a trace amount of Aalpha chain and no gamma chain was detected in the plasma of the proband.

Afibrinogenemia↗

PubMed2000

[Management strategy for patients with coronary artery disease associated with valve disease].

BACKGROUND: The indication of combined operation of coronary artery bypass (CAB) and valve surgery is controversial. METHODS: Between April 1992 and January 2000, 13 patients underwent a combined operation with CAB and valve replacement, and 4 patients (2 were overlapped) who had had a previous CAB underwent a reoperative valve replacement. RESULTS: One patient who underwent AVR and reCAB 11 years after the initial CAB died. Another patient with preoperative MRSA pneumonia and received MVR and CAB died 4 months after surgery with MRSA sepsis. However, others showed an excellent post-operative course. The causes of necessitating the reoperation were: unawareness of aortic stenosis at the initial emergency CAB in 1 patient, progression of aortic stenosis in 1 patient, progression of aortic regurgitation in 1 patient, and progression of mitral regurgitation in 1 patient. CONCLUSION: The results of the combined CAB and valve replacement operation were acceptable. Patients with mild-moderate valve disease should be considered as candidates for valve surgery at the time of CAB.

Aged↗

PubMed2000

[A case report of a successful surgical treatment for infective endocarditis involving four valves in a elderly patient with ventricular septal defects].

A 72-year-old female was examined because of acute congestive heart failure. Echocardiogram revealed vegetations on aortic and pulmonary valve, regurgitation of four valves, and perimembraneous ventricular septal defect. Aortic valve replacement, mitral valve replacement, repair of tricuspid valve using a Carpentier ring, partial resection of pulmonary valve, and direct closure of VSD was performed. Pathological finding of resected valves showed acute endocarditis. A patient resumed social activities after surgery.

Aged↗

PubMed2000

Histochemical correlates of (15)O-water-perfusable tissue fraction in experimental canine studies of old myocardial infarction.

UNLABELLED: A method has been proposed to quantitate the myocardial water-perfusable tissue fraction (PTF) in the area of hypoperfused asynergic segments using (15)O-water (H2(15)O) and PET. This study investigated the histochemical correlates of PTF (and perfusable tissue index, PTI) in a canine model of old myocardial infarction. METHODS: Myocardial infarction was produced in 12 mongrel dogs, and PET was performed 1 mo later, providing quantitative parametric images of PTF, regional myocardial blood flow (MBF), and extravascular density from H2(15)O, (15)O-carbon monoxide, and transmission datasets. At the end of scanning, the myocardium was sectioned, and the PET images were compared directly with the corresponding myocardial sections. RESULTS: The distribution of tissue necrosis identified by histochemical staining corresponded well with the defect in PTF but not in MBF. PTF agreed with the equilibrium images of myocardial H2(15)O distribution, obtained after injection of a large bolus of H2(15)O. The defect surface area identified on PTF agreed well quantitatively with the morphometric estimates of the surface area of myocardial infarction. PTI agreed with the absolute proportion of histochemically defined normal myocardium (0.87 +/- 0.09 and 0.83 +/- 0.08, respectively; P < 0.01). Both PTF and PTI decreased significantly in segments of myocardial infarction and showed a significant difference between the transmural and nontransmural myocardial infarction. CONCLUSION: The absolute mass and proportion of histochemically defined noninfarcted tissue may be quantitated with PTF and PTI in the area of myocardial infarction segments.

Animals↗

PubMed2000

Effects of clinostat-microgravity on bone and calcium metabolism in rats.

Decreases in bone minerals and tissue volume after space flight have been observed in humans and animals, with a variety of results. Such data obtained from space flight experiments have given unsatisfactory results due to short periods of space flight and differences in age, body weights, and strain of animals used. Therefore, ground-based animal models have been developed in order to elucidate changes in bone affected by space flight. For example, a tail-suspended rat model has been established to study the effects of microgravity on bones by producing hind limb unloading. However, problems with this model due to the remaining forelimb loading and the unusual changes in blood current require the development of a new model simulating the physiological conditions of space flight. So we developed a three-dimension clinostat as an apparatus to produce a simulated microgravity similar to space flight by rotating rats equally in all directions. The purpose of the present study is to examine the effects of clinostat-microgravity on bone metabolism in rats.

Adrenal Glands↗

PubMed1999

Myocardial oxygen consumption is unchanged but efficiency is reduced in patients with essential hypertension and left ventricular hypertrophy.

BACKGROUND: Patients with hypertension and left ventricular hypertrophy (LVH) are prone to develop heart failure. We tested the hypothesis that compensatory LVH is associated with normalization of myocardial oxygen consumption and that this occurs at the expense of a decrease in the ratio between cardiac work and oxygen consumption (efficiency). METHODS AND RESULTS: Nine hypertensive men with LVH (LVH+) (age 42+/-2 years), left ventricular mass index (LVMI) 161+/-8 g/m(2), blood pressure (BP) 145+/-16/88+/-10 mm Hg (mean+/-SD); 8 hypertensive men without LVH (LVH-) (age 39+/-5 years, LVMI 107+/-15 g/m(2), BP 140+/-15/90+/-11 mm Hg); and 10 normotensive men (CONT) were studied. Myocardial blood flow, oxygen consumption, and glucose uptake were measured during euglycemic hyperinsulinemia using PET techniques. LV dimensions, volumes, and workload were determined by echocardiography, and efficiency was calculated. Myocardial workload (2.5+/-0.8 versus 3.0+/-0.6 versus 2. 3+/-0.5 mm Hg. mL. min(-1). g(-1) for CONT versus LVH- versus LVH+; P<0.05, LVH- versus LVH+), myocardial blood flow (0.84+/-0.16 versus 1.06+/-0.22 versus 0.81+/-0.09 mL. g(-1). min, respectively; P<0.05, LVH- versus other groups) and oxygen consumption (0.09+/-0.02 versus 0.14+/-0.03 versus 0.11+/-0.01 ml. g(-1). min(-1), respectively; P<0. 05, LVH- versus other groups) were increased in the LVH- group. Myocardial efficiency was reduced in the LVH+ group (18.1+/-4.1% versus 15.1+/-2.3% versus 13.5+/-1.9%, respectively; P<0.05, LVH+ versus CONT). CONCLUSIONS: Myocardial oxygen consumption per unit weight is increased in hypertensive patients without LVH but is normal in those with LVH. The normalization of oxygen consumption via hypertrophy occurs at the expense of efficiency, which may predispose hypertensive patients with LVH to heart failure.

Adult↗

PubMed1999

Molecular identification of a eukaryotic, stretch-activated nonselective cation channel.

Calcium-permeable, stretch-activated nonselective cation (SA Cat) channels mediate cellular responses to mechanical stimuli. However, genes encoding such channels have not been identified in eukaryotes. The yeast MID1 gene product (Mid1) is required for calcium influx in the yeast Saccharomyces cerevisiae. Functional expression of Mid1 in Chinese hamster ovary cells conferred sensitivity to mechanical stress that resulted in increases in both calcium conductance and the concentration of cytosolic free calcium. These increases were dependent on the presence of extracellular calcium and were reduced by gadolinium, a blocker of SA Cat channels. Single-channel analyses with cell-attached patches revealed that Mid1 acts as a calcium-permeable, cation-selective stretch-activated channel with a conductance of 32 picosiemens at 150 millimolar cesium chloride in the pipette. Thus, Mid1 appears to be a eukaryotic, SA Cat channel.

Amino Acid Sequence↗